接下来是 Downward API，它的作用是：让 Pod 里的容器能够直接获取到这个 Pod API 对象本身的信息。
apiVersion: v1
kind: Pod
metadata:
name: test-projected-volume
spec:
containers:
- name: test-secret-volume
image: busybox
args:
- sleep
- "86400"
volumeMounts:
- name: mysql-cred
mountPath: "/projected-volume"
readOnly: true
volumes:
- name: mysql-cred
projected:
sources:
- secret:
name: user
- secret:
name: pass
apiVersion: v1
kind: Pod
metadata:
name: test-downwardapi-volume
labels:
zone: us-est-coast
cluster: test-cluster1
rack: rack-22
spec:
containers:
- name: client-container
image: k8s.gcr.io/busybox
command: ["sh", "-c"]
args:
- while true; do
if [[ -e /etc/podinfo/labels ]]; then
echo -en '\n\n'; cat /etc/podinfo/labels; fi;
sleep 5;
done;
volumeMounts:
- name: podinfo
mountPath: /etc/podinfo
readOnly: false
volumes:
- name: podinfo
projected:
sources:
- downwardAPI:
items:
- path: "labels"
fieldRef:
fieldPath: metadata.labels
1. 使用fieldRef可以声明使用:
spec.nodeName - 宿主机名字
status.hostIP - 宿主机IP
metadata.name - Pod的名字
metadata.namespace - Pod的Namespace
status.podIP - Pod的IP
spec.serviceAccountName - Pod的Service Account的名字
metadata.uid - Pod的UID
metadata.labels['<KEY>'] - 指定<KEY>的Label值
metadata.annotations['<KEY>'] - 指定<KEY>的Annotation值
metadata.labels - Pod的所有Label
metadata.annotations - Pod的所有Annotation
2. 使用resourceFieldRef可以声明使用:
容器的CPU limit
容器的CPU request
容器的memory limit
容器的memory request
[root@dock01 ~]# kubectl exec -it test-downwardapi-volume -- /bin/sh
/ # ls
/ # cat /etc/podinfo/labels
cluster="test-cluster1"
rack="rack-22"
zone="us-est-coast"/ #
[root@dock01 ~]# kubectl exec -it scan-downwardapi-volume -- /bin/sh
/ # cat /etc/podinfo/labels
scan-downwardapi-volume/ #
[root@dock01 ~]# kubectl exec -it tlcb-downwardapi-volume -- /bin/sh
/ # cat /etc/podinfo/labels
37ac71cb-c079-4b35-9235-ee7d1d975bca/ #